An optical fibre composite electric power cable is a cable wherein an optical fibre is included in an electric power cable. Such optical fibre composite electric power cable may for example be used in offshore applications, such as submarine power and/or communication cables. Another example is in installation environments that require monitoring of the operation of electricity, wherein the optical fibres may be used for detecting temperature distribution of the power cable.
Two cable ends often need to be connected to each other, for example when installing the cables in the application at hand, or in a jointing process if the cable is broken and require repair. When jointing the optical fibre cable of the optical fibre composite electric power cable, it is realized that a certain extra length has to be added in order to accomplish the jointing of the cable ends.
JP 59212813 describes a way of handling the extra length required for jointing cable ends of an optical fibre cable. In accordance with the teachings of this document, the extra length is handled by arranging the optical fibre cable along and between the power cables in a wave-like pattern. The presented solution is adequate for rather thin optical fibres, which can easily be bent in any desired manner. However, as the diameter of the optical fibre cable increases difficulties occur in that the length over which the extra length is arranged increases considerably, and may range up to several hundreds of meters. Further, such large-diameter optical fibre cables cannot be bent in just any way and for fibre cables having diameters exceeding a certain value this solution is not at all applicable. Further yet, the outer dimensions of the optical fibre composite electric power cable may be increased, which causes difficulties for example during transportation of the cable.
From EP 646 817 A2 means for jointing fibre optical cables is known. In particular, a fibre optic jointing cabinet is used for repairing the fibre optic cable. This solution functions well for repairs in an existing installation, for example in an offshore installation. A disadvantage is that the joint is rigid, and for repairs performed before cable installations such rigid joints present problems in that the transportation and other handling of the cable is rendered more difficult.
Another disadvantage is that the outer dimension of the composite electrical/fibre optical cable is increased and the handling is again made more complicated. Further, such an increased dimension cannot be handled during manufacturing of the composite electrical power cable, should the fibre optical cable be broken at the manufacturing, since the manufacturing machines etc. are adapted for the originally intended dimension.
In view of the above, it would be desirable to provide an improved cable joint, which can be used for different kinds of repair needs and for optical fibre cables of any diameter.